NOx regulations under way after 24-year delay.
D000397:Air Pollution / Q000517:prevention & control*; D004777:Environment; D009589:Nitrogen Oxides / Q000592:standards*; D011050:Policy Making; D011210:Power Plants; D013997:Time Factors; D014481:United States; D014484:United States Environmental Protection Agency
D009589:Nitrogen Oxides